Association between ambient temperature and years of life lost of external causes of death in 16 prefecture-level regions of Yunnan Province.

Background: Many injury deaths are related to the environment. This study examined the impact of ambient temperature on external causes of death in Yunnan Province.

Methods: Data on external causes of death and meteorological information were collected from 2014 to 2020 across 129 counties and districts of Yunnan Province. We estimated associations of the years of life lost (YLL) and its attributable fraction (AF) with temperature using a distributed lag non-linear model in each city and then pooled them in a multivariate meta-regression.

Results: This study included 191 115 external causes of death and daily YLL was 2338.1 years. The relationship between mean temperature and YLL was found to be U-shaped. The AF of the YLL was 12.65% (95% empirical CI (eCI) 7.80% to 16.45%), 18.54% (95% eCI 8.91% to 23.56%) and 15.79% (95% eCI 8.83% to 20.07%) for external causes of death, traffic accidents and other external causes, respectively. Most of the disease burden was attributed to heat temperature. In the disease burden caused by temperature, males, individuals under 75 years old and those of Han ethnicity were mainly affected by heat temperature; individuals over 75 years old and minority populations were mainly affected by cold temperatures. Non-farmers are more affected by temperature than farmers.

Conclusions: The findings suggest that ambient temperature impacts external causes of death, and the results vary by gender, age, ethnicity and occupation. The study shows the importance of implementing preventive measures targeting both the general population and vulnerable groups in order to address external causes of death in future adaptation policies.